Hermetically sealing samples may present a challenge in remote or hostile environments, such as the moon, Mars, an irradiated environment, a high temperature/pressure environment, etc. For instance, for a proposed rover mission to Mars in 2020, NASA wishes to collect, document, and package samples for future collection and return to Earth. However, such samples must be able to be hermetically sealed and left on Mars for an extended period of time (e.g., at least five Mars years) without loss of scientific value. In other words, the scientific integrity of the samples must be preserved during the interval between collection and subsequent analysis through effective sealing of the samples. This is needed to prevent loss of water or OH-bearing samples, and also to prevent hydration of anhydrous samples. The Mars 2020 mission proposes to store samples in individually sealed thin-wall sample tubes. The sealing method is desired to be compatible with a smooth thin-wall tube and robust to variations in tube diameter, surface roughness, dust, temperature, vibration, and shock.
Current all-metal radially expanding plugs for hermetic sealing require reaming out of the hole to seat the plug prior to installation, a torque actuator to initiate expansion, thermal control for thermally activation, explosives for explosive welding, or long tapped rod assemblies that add increased mass and storage volume. Accordingly, an alternative plug design may be beneficial.